Note 15 - Stock-based Compensation - Unrecognized Stock-based Compensation Expense (Details) $ in Thousands	Mar. 31, 2020 USD ($)
Remainder of 2020	$ 2,430
2021	2,351
2022	1,565
2023	756
2024	374
2025	38
Total estimated expense	7,514
Stock Appreciation Rights (SARs) [Member]
Remainder of 2020	263
2021	304
2022	249
2023	174
2024	68
2025	9
Total estimated expense	1,067
Restricted Stock [Member]
Remainder of 2020	958
2021	1,094
2022	826
2023	582
2024	306
2025	29
Total estimated expense	3,795
Restricted Stock Units (RSUs) [Member]
Remainder of 2020	202
2021	1
2022	0
2023	0
2024	0
2025	0
Total estimated expense	203
Performance Shares [Member]
Remainder of 2020	1,007
2021	952
2022	490
2023	0
2024	0
2025	0
Total estimated expense	$ 2,449